If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

First dog genome sequence decoded

The wide coverage of this breakthrough gives some indication of how special it is that the cavalier was also chosen for decoding, in the project spearheaded by Dr Clare Rusbridge and Penny Knowler. They fought hard to get the CKCS considered for this rare opportunity as part of the search for a gene or genes for SM.

BOSTON (Reuters) - How can a Chihuahua and a Doberman belong to the same species? A detailed analysis of the dog genome answers these questions and will also shed light on human health and biology, scientists said on Wednesday.

A U.S. government-funded study of the complete genetic map of an inbred boxer named Tasha not only helps explain how poodles differ from jackals, but might offer insights into bone cancer, blindness and epilepsy, the researchers said.

"It's going to make the identification of many disease genes 50 times easier," Dr Eric Lander, a gene expert at the Broad Institute at the Massachusetts Institute of Technology and Harvard University who helped coordinate the study, told a news conference.

"It ought to be possible in the next three to four years to identify a gene for bone cancer in dogs."

Writing in the science journal Nature, the researchers at 15 institutions described how they compared the genetic blueprint of the boxer with 10 other breeds. They also compared the dog genome to the already-completed maps of human genes, mice, rats and chimpanzees.

The team, led by the Broad Institute's Kerstin Lindblad-Toh, sequenced the 2.4 billion letters of Tasha's DNA, representing 39 pairs of chromosomes. There lies one big difference between dogs and people -- human genes are found on just 23 pairs of chromosomes.

The researchers also compiled a catalog of 2.5 million single-nucleotide polymorphisms -- one-letter changes in the genetic code -- that differ among the 10 breeds of dogs studied.

The genes that make some dogs big and others little, that give some dogs long snouts and others pushed-in faces, and that predispose some dogs to certain diseases provide a convenient laboratory for studying biology, medicine and evolution.

"The hundreds of years of careful inbreeding to produce the various breeds have delivered a geneticist's dream model for human genetic disease," Hans Ellegren of Uppsala University in Sweden wrote in a commentary.

In 2003, teams at The Institute for Genomic Research and genome entrepreneur Craig Venter's Center for the Advancement of Genomics in Rockville, Maryland, published a genetic map of Venter's pet poodle.

But the U.S. government-funded team said their study was more complete and systematic.

"Until now we only had little shreds of the dog genome. We now have the entire book from end to end, ready to read," Lander said.

The researchers, who staged their news conference at a dog show in Massachusetts, were clearly fans of man's best friend.

"The incredible physical and behavioral diversity of dogs -- from Chihuahua to Great Danes -- is encoded in their genomes. It can uniquely help us understand embryonic development, neurobiology, human disease and the basis of evolution," Lander said.

Elaine Ostrander, chief of cancer genetics at the National Human Genome Research Institute, said dog genetics could help narrow down the search for human disease genes.

"The leading causes of death in dogs are a variety of cancers, and many of them are very similar biologically to human cancers," Ostrander said.

"They breathe the same air, drink the same water and walk across the same lawns that we do," added Dr. Matthew Breen, associate professor of genomics at North Carolina State University, who worked on the project.

"Cancers that dogs get are exactly the same as the cancers that we get."

UK-based researchers Clare Rusbridge and Penny Knowler and their Canadian collaborators Guy Rouleau and Berge Minassian have been successful in their submission to the Mammalian Genotyping Service at the Marshfield Clinic in Wisconsin (USA) for a full CKCS genome scan. The research is initially into syringomyelia but hopefully will be extended to looking for candidate genes for MVD as well.

The research, undertaken by a joint veterinary and human medical group, will benefit both 'man and his best friend'. Syringomyelia in CKCS is an excellent model for research into the condition in humans, and geneticists are interested in validating findings from the CKCS research in people. Finding the gene and learning how it works would help the understanding of the disorder for better diagnosis, clinical management and ultimately, prevention. For biologists, these studies will provide new insights into the poorly understood process of normal development of craniocerebral structures of the central nervous system. The researchers say that many people worldwide will benefit from this research -- and are pleased that so many 'ordinary' people worldwide are contributing to make it possible.

The genome scan will identify markers which can then be used to identify the gene/s responsible for the disorder causing syringomyelia. The same team have already been successful in identifying the canine gene for Lafora's disease. The research is expected to take several years but the first stage will hopefully produce a DNA test which will enable informed breeding decisions.

The researchers say that due to the generosity of clubs, research projects and individuals, they have collected enough DNA samples to start the genome scan. Therefore they no longer require DNA from CKCS dogs with syringomyelia. However, the researchers are still anxious for DNA from dogs of breeds other than cavaliers that have syringomyelia.

The researchers acknowledge that the entire project could not have been undertaken without the support of the UK DNA Archive for Companion Animals which provided DNA extraction and storage from samples taken in the UK.